Effects of exercise mode and intensity on retinal microvascular structure and function in heart failure patients with preserved ejection fraction: a pilot exercise intervention trial

Purpose: We aimed to investigate the effect of different exercise modes on retinal microvascular endothelial function in patients with HF with preserved ejection fraction (HFpEF). Methods: Twenty-eight patients were randomly allocated to either a moderate (MCT) or high intensity interval training (HIIT) group for 12 weeks. Retinal microvascular health was investigated by analyzing central retinal arteriolar (CRAE) and venular (CRVE) diameter equivalents, the arteriolar-to-venular diameter ratio (AVR) and the dynamic arteriolar (aFID) and venular (vFID) flicker light-induced dilation response. Results: Twenty patients (mean age 70±9years) were included in the final analysis. After HIIT, AVR increased (0.80±0.03 vs. 0.83±0.04, p=0.03) due to arteriolar widening. CRAE increased (157±18µm vs. 164±18µm, p=0.05) but CRVE did not change (196±27µm vs. 197±24µm, p=0.56). After MCT, AVR also increased (0.80±0.08 vs. 0.83±0.06, p=0.02) without significant changes in CRAE (160±19µm vs. 165±18µm, p=0.07) or CRVE (201±14µm vs. 199±14µm, p=0.40). aFID improved after MCT (2.1±1.6% vs. 3.1±1.8%, p=0.03) but not after the HIIT intervention (2.1±1.7% vs. 2.4±2.1%, p=0.60). vFID did not statistically significant change neither in the HIIT (4.4±2.2% vs. 3.4±1.9%, p=0.06) nor in the MCT (4.3±2.2% vs. 5.5±4.1%, p=0.26) group. Conclusion: MCT and HIIT are both adequate therapy options to improve microvascular health in patients with HFpEF.